Method and Device for Managing Multicast Groups

1. A multicast router situated in a data network system between sources that send multicast packets to at least one multicast group address and one or more hosts that request data from the multicast group address and sources, the multicast router comprising: one or more downstream network interfaces; a storage medium that stores for a downstream network interface and multicast group address at least one INCLUDE source record and at least one EXCLUDE source record, the INCLUDE source record containing information about include source lists derived by data requests made by the one or more hosts and the EXCLUDE source record containing information about exclude source lists derived by data requests made by the one or more hosts; a source-timer for each of the sources in the include and exclude source lists, the exclude source lists including a Requested List containing a list of sources having a source-timer of a value greater than zero and an Exclude List containing a list of sources having a source-timer of a value zero; and wherein the downstream network interface transmits for each multicast group address multicast packets to the hosts based on the information of the at least one INCLUDE source record and the at least one EXCLUDE source record by transmitting for each INCLUDE source of a multicast group address having a source-timer of a value greater than zero multicast packets through the network interface and also transmitting multicast packets of the remaining sources of the multicast group address through the network interface except the EXCLUDE sources from the Exclude List; and the multicast router using a host-router multicast routing protocol based on the IGMP (Internet Group Management Protocol) or the MLD (Multicast Listener Discovery) protocol to communicate with the one or more hosts and a router-router multicast routing protocol to communicate with at least one other multicast router situated between the multicast router and the sources.

2. The multicast router according to claim 1 , wherein the INCLUDE source record stored in the multicast router contains the union of all the include source lists requested from the hosts.

3. The multicast router according to claim 1 , wherein the EXCLUDE source record stored in the multicast router contains the intersection of all the exclude source lists requested from the hosts.

4. The multicast router according to claim 1 , wherein the multicast router stores for the downstream network interface and multicast group address only one INCLUDE source record and only one EXCLUDE source record, the INCLUDE source record containing the union of all the source lists requested from the hosts and the EXCLUDE source record containing the intersection of all the exclude source lists requested from the hosts.

5. The multicast router according to claim 1 , wherein the at least one INCLUDE source record for the downstream network interface and multicast group address comprises (multicast-address, INCLUDE, {source list and timers}) and the at least one EXCLUDE source record comprises (multicast-address, EXCLUDE, {source list and timers}), where {source list and timers} comprise a list of elements {source-address and source-timer}, and where source-address comprises the source IP address, and where source-timer comprises a timer associated to the source.

6. The multicast router according to claim 1 , wherein the multicast router contains executable instructions for updating the at least one INCLUDE source record and the at least one EXCLUDE source record upon receiving a state message or change of state message originating from the one or more of hosts.

7. The multicast router according to claim 1 , wherein the multicast router is capable of receiving a state message originating from one or more hosts that includes instructions about a method the multicast router must apply to set up routing trees from the source to the multicast router.

8. The multicast router according to claim 1 , wherein the multicast router stores executable instructions for (1) keeping, for each downstream network interface and multicast group address, at least two separate records: the INCLUDE source record and the EXCLUDE source record, and (2) updating the INCLUDE source record and the EXCLUDE source record, for each multicast group address, when the multicast router receives, through the multicast router's downstream network interface, a message containing information about an include source list and information about an exclude source list originating from one or more of the hosts.

9. The multicast router according to claim 1 , wherein for a multicast group address the multicast router includes an upstream network interface that requests the data from the source via the at least one other multicast router situated within a routing tree between the sources and the multicast router, the upstream network interface communicates with the at least one other multicast router via the router-router multicast routing protocol to request the data from the sources using the information in the INCLUDE source record and the information in the EXCLUDE source record to permit a direct connection with the sources through a shortest path tree of the routing tree.

10. The multicast router according to claim 9 , wherein the router-router multicast routing protocol is a version of a PIM (Protocol Independent Multicast) protocol.

11. The multicast router according to claim 1 , wherein for a multicast group address the multicast router includes an upstream network interface that requests the data from the source via a plurality of multicast routers which include a Rendezvous Point Router, the plurality of multicast routers situated within a routing tree between the source and the multicast router, the routing tree including rendezvous point trees (RPT) and shortest path trees (SPT) for the source, the upstream network interface communicates with the plurality of multicast routers via the router-router multicast routing protocol to request the data from the sources using the information in the INCLUDE source record and the information in the EXCLUDE source record to permit a direct connection with the source via the shortest path trees without the need to use the rendezvous point trees.

12. The multicast router according to claim 11 , wherein the router-router multicast routing protocol is a version of a PIM (Protocol Independent Multicast) protocol.

13. The multicast router of claim 1 , wherein upon receiving in a downstream network interface an IS_IN(x) type message for a multicast group address no EXCLUDE source records for the multicast group are modified.

14. The multicast router of claim 1 , wherein upon receiving in a downstream network interface an IS_EX(x) type message for a multicast group address no INCLUDE source record is modified.

15. The multicast router according to claim 1 , wherein for each downstream interface and multicast group address the multicast router first transmits to the hosts data from the sources in the include source lists and then transmits to the hosts data from all the remaining sources except those sources from the Exclude List.

16. The multicast router according to claim 1 , wherein the multicast router is configured to receive messages originating from the one or more hosts requesting the multicast router to stop sending data from a multicast group address and a source and to send Group-And-Source-Specific Query type messages to the one or more hosts, the multicast router storing executable instructions for determining whether one or more other hosts are receiving data from the multicast group address and source upon receiving the stop request using the at least one INCLUDE source record and the at least one EXCLUDE source record and to continue sending data from the multicast group address and source to the one or more other hosts without sending a Group-And-Source-Specific Query messages to the one or more other hosts receiving data from the multicast group address and source.